1. Field of the Invention
This invention relates to a contents copying management system that can suitably be applied, for instance, to recording/reproducing apparatus having a functional feature of reproducing the contents recorded on a DVD (digital versatile disc) or a CD (compact disc) (to be referred to as recorded contents hereinafter) and that of copying the recorded contents onto a hard disk.
2. Description of the Related Art
Recording/reproducing apparatus such as DVD-R (digital versatile disc—recordable) recorders and CD-R (compact disc—recordable) recorders adapted to copying various contents including image data and sound data onto a recording medium such as DVD-R or CD-R have been widely sold in recent years. Such recording/reproducing apparatus are intended to be used personally and provided with various measures for preventing illegal copying.
Popular techniques for preventing illegal copying include the color strip method, the AGC (automatic gain control) pulse method and the digital water mark method.
For instance, a replay-only DVD player using the color stripe method or the AGC pulse method is adapted to send out an output signal prepared by adding a pulse of a color burst signal and that of a vertical synchronous signal to the replay signal obtained by reproducing the recorded contents of a DVD to a DVD-R recorder for recording.
With this arrangement, it is impossible to correctly record the output signal by the DVD-R recorder because the added pulses degrade the quality of the reproduced image.
A DVD-R recorder that uses the digital watermark method is adapted to read a watermark of recorded contents carrying a pattern called the watermark and prohibit copying if the watermark says to do so.
Beside the above listed popular methods, a method as described below has also been proposed. A recording/reproducing apparatus using the proposed method stores a value that is specific to the apparatus in a nonvolatile memory and records the specific value on a recording medium with contents when copying the contents. When the recording/reproducing apparatus is operated to reproduce the contents that have been copied on the recording medium (to be referred to as copied contents hereinafter), the apparatus collates the specific value recorded on the recording medium and the specific value stored in the nonvolatile memory in the recording/reproducing apparatus itself and determines if the copied contents are allowed to be replayed only by the recording/reproducing apparatus or not on the basis of the outcome of the collation. If the apparatus determines that the copied contents have been illegally copied, it restricts any reproduction (see, inter alia, Japanese Patent Application Laid-Open Publication No. 2001-195826 (Column 3, FIG. 1).
If recorded contents of a DVD are copied on a writable DVD-RW for the purpose of personal use by means of a recording/reproducing apparatus using such a method, the copied contents can be replayed only by the recording/reproducing apparatus that has been used for recording the contents on the DVD-RW but cannot be replayed by any other recording/reproducing apparatus.
However, when the DVD is loaded on some other recording/reproducing apparatus, it is no longer possible for the recording/reproducing apparatus using the method to prevent the contents recorded on the DVD from being copied by the some other recording/reproducing apparatus.
For example, when a person borrows a DVD from an authorized user who purchased the DVD (to be referred to as authorized user hereinafter), the person who borrowed the DVD can copy the contents recorded on the DVD for the purpose of personal use by means of a recording/reproducing apparatus that the person owns. Then, if the person who borrowed the DVD copies the recorded contents only for the purpose of personal use, a third person who borrows the DVD carrying the copied contents from the owner of the DVD carrying the copied contents can recopy plural copied contents. Thus, it is consequently possible to make many illegal copies.